Electrocatalytic hydrodechlorination of chlorinated PPCPs at oxygen-enriched vacancies Ti4O7/Ti loaded Pd electrode and mechanism study

In order to improve the metal utilization of the noble metal Pd and the catalytic activity of the reaction, a novel and efficient Pd/Ti4O7/Ti electrode was prepared by introducing a Ti4O7 intermediate layer for electrocatalytic hydrodechlorination (EHDC) of chlorinated pharmaceuticals and personal care products (PPCPs). The presence of oxygen vacancies (Ov) on the Ti4O7 surface was confirmed by electron paramagnetic resonance (EPR). The results showed that the introduction of Ti4O7 increased the electrochemical active surface area electrode (ECSA) of the Pd/Ti4O7/Ti electrode, accelerated the electron transfer rate on the catalyst surface, and promoted the generation of electron-rich Pd, which in turn improved the dechlorination efficiency. The Pd/Ti4O7/Ti electrode had a removal efficiency of 99.6% for florfenicol (FLO) within 180 min. Meanwhile, the removal efficiency of the Pd/Ti4O7/Ti electrode was still above 95% in seven cycles, which significantly improved the catalytic activity and stability compared with that of the Pd/Ti electrode. In addition, the reaction pathway for the electrocatalytic hydrodechlorination process of FLO at Pd/Ti4O7/Ti electrode was proposed. The ecotoxicity of the pollutants was also evaluated by the Toxicity Estimation Software Tool (T.E.S.T) model. In this study, an efficient electrocatalyst for EHDC was explored, and the Pd/Ti4O7/Ti electrode provided strong support for pollutant removal.